Process and apparatus for making steel



Sept. 22, I 925.

A. A. RACKOFF ET AL PROCESS AND APPARATUS FOR MAKING STEEL Filed March 1, 1923 lNVENTORS Patented Sept. 22, 1925.

UNITED STATES PATENT OFFICE.

morn: A. aacxorr,

) PROCESS AND APPARATUS FOR MAKING STEEL.

Application fll ed Iaroh- 1, 1928. Serial No. 822,119.

To all whom it may concern:

Be it known that we, ADOLPH A. RAOKOFF and JAMES Loms SHARKEY, citizens of the United States, and residents of Wilkinsburg and New York, res ectively, in the counties of Allegheny and ew York, rlispectivel and States of Pennsylvania and ew Yor respectively, have invented a new and useful Improvement in Processes and Apparatus for Making Steel; and we do hereby declare the following to be a full, clear, and exact description thereof.

Our invention relates to the handling of molten steel and other metals while the metal is being transferred to molds from open hearth or other metallurgical furnaces.

The object of our invention is to improve the quality of the metal by removing impurities therefrom through the combined action of mechanical agitation and sub-atmospheric pressure. The agitation is relied upon to bring solid and liquid slag impurities to the surface of the metal while it is passing from the furnace to the pouring ladle and the sub-atmospheric pressure is employed to extract certain gases which are present in solution in the molten metal.

To these ends, we provide a ladle adapted to receive metal from an open hearth furnace, or other metallurgical furnace, and to deliver the metal into molds. We also pro vide means for interposing obstructions or battles in the path of the flowing metal in such a way as to cause the metal to" be agitated before it falls into the ladle, and we place the ladle, and preferably the agitatmg channel, in a artial vacuum by means of a suitable suction pump. Other novel features of our invention include means for skimming slag from the metal on its way to the ladle, an arrangement of gates for directing the flow of the metal, and a remov able vacuum cap for covering the ladle and the agitating channel.

Our present invention is an improvement over the sytem of handling molten metal described and claimed in the prior application of Adel h A. Rackofi", filed October 4, 1920, Serial 0. 414,581, and we employ certain features of the said prior system in carrying out our present invention.

In the accompanying drawing, Fig. 1 is a vertical sectional view showing somewhat diagrammatically a set of apparatus constructed in accordance with our invention,

tially gas-ti ht cover.

the section being taken substantially on the line 1-1, Fig. 2; Fig. 2 is a plan view of the same apparatus; Fig. 3 is another vertical sectional view taken substantially on the hue 3-3, Fig. 2; and Fig. 4 is a plan view of the same apparatus with the vacuum cap removed.

In the drawing, the numeral 2 indicates a portion of an open hearth steel furnace having a tapping notch 3 which discharges the molten metal into a runway 4 leading to a ladle device, with which our invention is particularly concerned. This device includes a body portion 5 which may be of any construction usual in ladles for handling metal, and which may have in its bottom a pouring opening 6 controlled by a plug 7. Trunmons 8 are provided for lifting and transporting the ladle.

The top of the ladle 5 is covered by a member 9 which carries the agitating, skimming and flow-controlling arrangements, and above the member 9 is a vacuum cap 10 which is so shaped as to form a substan- The joints between the ladle 5, t e member 9 and the cap 10 may be luted with clay or the like.

The member 9 is provided with a straight channel 11 communlcating with the runway 4 and with a circularl curved channel 12 which receives the mo ten metal from the straightchannel 11 and conveys it in a generally circular path to an opening 13 through which the metal falls into the body of the ladle 5. Bafiles 14 extend into the channel 12 and cause the molten metal to move in a zigzag path which agitates the metal and brings the slag to the surface. Beyond the baflles 14 the channel 12 is deepened, as shown at 15, to form a settling and storing rece tacle which receives the metal temporarily efore it enters the body of the ladle.

We provide means for removing slag from the molten metal at two points durlng its passage throu h the channels described above. One 0 these slag-removing means consists of a chute 16 communicating with the straight channel 11 at a point above the bottom thereof, and the other consists of a spout 17 leading off from the curved channel 12 beyond the bafiles 14 and from a point the flow'of metal and slag in the above described paths; A gate 20 is provided near i the inlet end of the straight channel 11 for entirely shutting 011' the inlet to the ladle. A gate 21 controls communication between the channel 11 and the slag chute 16. A gate 22 controls the passage of metal from the straight channel 11 into the curved channel 12. A gate 23 controls the flow from the channel 12 into the slag spout 17, and a gate 24 controlsthe flow of metal from the reservoir 15 intothe body of the ladle. All of these gates are composed of refractory material and slide in refractory"-guidewa s 25 carried by the cover member 9. T e gates may be raised and lowered by any ordinary means, which it is not considered necessary to illustrate in detail, since such arrangements are common in the art.

Pipes 26, 27 and 28 extend through the top of the vacuum cap 10, and all communicate with a horizontal pipe 29 which is connected to a suitable vacuum pump, not shown. The pipes 26 and 27 communicate with the space between the cap 10 and the cover member 9, while the pipe 28 extends through the cover member and communicates with the ace in the body of the ladle. It will be evi ent that various other arrangements of pipes may be employed to place the interior of the apparatus under reduced pressure. For example, one or more suction pipes may be inserted through the side walls of the ladle 5 instead of inserting the pipe 28 into the ladle from above, as shown.

In the operation of handling metal by the use of the apparatus described above, the

ladle is connected to the furnace in the,

manner shown, with the gates 20 and 22 open and the gate 21 closed. The metal which first flows from the furnace is thus caused to flow through the curved channel 12 around the bafiles 14 which agitate the metal and cause any slag which maybe contained within the body of the metal to rise to the surface, where it remains since it is lighter than the metal and is not subjected to any ressure tending to submerge it again. Such s ag may be skimmed oif through the slag spout 17, the entrance to which is located near the top of the stream of molten metal, and the gate 23 bein raised sufliciently for this purpose. T e metal then passes into the depression or reservoir 15- mam the slag chute 16 and passes to the sla cat.

Throughout the operation, the la le is preferab y kept under reduced pressure by operating the vacuum pump to which the pipe 29 is connected. The gate 20 is sealed by the metal flowing beneath it, and if the slag gate 23 is openedit is preferably opened onl far enough to permit the slag to escape without permitting air to enter to a substantial extent. After the charge has been tapped from the furnace the gate 20 may be closed and the vacuum is maintained within the ladle as long as may be reguired,

depending upon the degree of desired and the time required the metal into molds. I

. The system described above produces metal that is thoroughly cleansed, both by the removal of slag and by the extraction of some or all of the dissolved gases.

It will be understood that the fore oing details of construction are shown an described herein merely for the purpose of illustrating our invention, and that our invention is by no means limited to this particular structure, but may be carried out by means of any other apparatus and with any variations in the steps of the process such as fall within the scope of the appended claims.

We claim as our invention:

ipuri cation or pouring 1. Metallurgical apparatus comprising a furnace, a container, means for conductmg molten metal from said furnace to said container, means for withdrawing slag impurities from the molten metal while passing fromthe said furnace to the said container, and means for subjecting said metal to subatmospheric pressure while passing from said furnace to said container.

2. Apparatus for making steel comprising a ladle, means for causing molten metal to flow horizontally toward the said ladle and then to drop vertically into the said ladle, means for withdrawing slag impurities from the said metal while fiowin toward said ladle, and means for maintaining said purifying means under sub-atmospheric pressure.

3. Apparatus for making steel comprising a'ladle, means for causing molten metal to flow in an indirect path and thence into the said ladle, baflies extending into the path of the flowing metal from the sides thereof and adapted to remove impurities from the said metal, and means for maintaining said flowdirecting and purifying means under subatmospheric pressure.

4. Apparatus for making steel comprising a ladle, means for causing molten metal to flow in an indirect path and thence into the said ladle, bafiles extending into the path of the flowing metal from the sides thereof and adapted to remove impurities from the said metal, and means for maintaining said flow-directing and purifying means under sub-atmospheric pressure and for also maintaining said ladle under subatmospheric pressure.

5. Apparatus for making steel comprising a la 1e, a cover therefor having a channel for directing molten metal around the said ladle and then permitting the metal to drop vertically into said ladle, and means for maintaining said cover and said ladle under sub-atmospheric pressure.

6. Apparatus for handling molten metal comprisin a ladle, a cover for the said ladle, sai cover being provided with an annular channel for conducting molten metal, a cap above said cover, and means for exhausting air from the interior of said cap and from the interior of'said ladle.

7. Apparatus for handling molten metal comprising a ladle, a cover for the said ladle said cover being provided with an annular channel for conducting molten metal, a cap above said cover, means for exhausting air and gases from the interior of said cap and from the interior of said ladle, and bafiles extending into said channel from opposite sides thereof.

8. Apparatus for handling molten metal comprising a ladle, a cover therefor provided with an annular channel having portions of successively increasing depth, the portion of greatest depth communicating with an opening leading into the interior of said ladle, means for conducting slag from said metal, gates for controlling the flow of molten material through said channel and through said slag-removing means, a cap above the said ladle and cover, and pipes extending through the said cap for maintaining the interior of the apparatus under sub-atmospheric pressure.

9. The process of making steel which comprises melting a charge in a furnace, conducting said molten charge from said furnace in the form of a stream, agitating said stream under sub-atmospheric pressure, and diverting the top portion of said stream to separate the slag contained therein from the main body of the stream.

In testimony whereof we the said Aoonrn A. RACKOFF and JAMES LOUIS SHARKEY, have hereunto set our hands.

ADOLPH A. RACKOFF. JAMES LOUIS SHARKEY. 

